Figure 1.

Positron emission tomography findings in migraine (left),¹⁴ cluster headache (centre),¹⁰ and experimentally induced head pain (right).⁹ Activation of rostral brainstem structures in migraine, and of posterior hypothalamic grey matter in cluster headache, seem relatively specific for the syndromes, as neither is seen in experimental ophthalmic division pain. The findings support the view that primary neurovascular headaches, migraine, and cluster headache are fundamentally disorders of the nervous system